I Really have no idea, why she's growing. I picked it up mostly for the covers(the other three I had to buy on line) as I had skimmed through the others and saw no growth. I did the same here and did, so I bought it. The story is a supposed to be part of a 10 series compilation that Double Take has said takes place in the universe of the 1968
Night of the living Dead film. Up until now this one was just about a group of radio stations having to make due during the zombie invasion. Now I've only read this series but the first two issues for each series can be read for free on their site. So I will eventually do that, 3 and 4 are 99 cents. As for figuring out the growth there seems to be a three month gap between releases and 4 came out this month so we will have to wait for five to get some answers. Attached is the preview for the 5th cover.
https://doubletakeuniverse.com/